Electronics International US-8A - Manual (Page 14)

These limits are only a starting point. More specific information on how to select the proper temperature limits
for your engine is provided below.
1. EGT’s:
The Exhaust Gas Temperatures are directly related to your engine’s ability to produce power. If any cylinder
has a problem producing power (fouled plug, burned or stuck valve, broken ring, intake leak, plugged
injector, timing problem, bad mag, etc.) the EGT’s for that cylinder will be abnormally high or low depend-
ing on the problem. Each cylinder on your engine operates differently and has a normal operating tempera-
ture of its own. The Ultimate Analyzer is capable of being programmed to match each cylinder on your
engine. When selecting the following limits, it is assumed your engine currently does not have a problem
and is operating properly.
A) Selecting the High EGT Limits: At 75% power, lean your engine to peak EGT. Record the EGT
readings for each cylinder. Program the High Limit for each cylinder 40’F above the recorded readings for
that cylinder. This is only a recommended limit. As you get to know your engine’s normal operating
temperatures you may want to adjust these limits accordingly.
B) Selecting the Lower EGT Limits: Set your aircraft up in a normal low cruise power condition. Adjust
the mixture full rich and wait for the EGT’s to stabilize. Once the EGT’s have stabilized, record the EGT
readings for each cylinder. Program the Lower Limit for each cylinder 40’F below the recorded readings for
that cylinder. This is only a recommended limit. As you get to know your engine’s normal operating
temperatures you may want to adjust these limits accordingly.
C) Selecting the EGT Differential Limit: Your engine’s EGT’s will vary for different power, altitude and
mixture settings. To further enhance the Ultimate Analyzer’s ability to detect a problem, set your aircraft up
in a normal cruise power condition. Lean your engine and wait for the EGT temperatures to stabilize.
Record the EGT’s for each cylinder. Set the Differential Limit for 40’F higher than the difference between
the hottest and coldest EGT readings (i.e., Hottest EGT - Coldest EGT + 40’F = Setting). This is only a
recommended limit. As you get to know your engine’s normal operating temperatures you may want to
adjust this limit accordingly.
2. TIT:
Running your engine with turbine inlet temperatures (TIT) above 1650’F can cause hairline thermal stress
cracks in the turbine housing. Also, it can cause detonation and preignition, which will lead to burned
valves, bent valve stems, broken rings and cracked exhaust systems. Controlling your TIT temperatures is
essential for turbo-charged aircraft.
The Ultimate Analyzer will continuously monitor your TIT in the scan mode. If the TIT exceeds 1650’F, the
Ultimate Analyzer will stop and light a bright red warning light over the display, immediately alerting the
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Selecting the Proper Limits Operating Information